1. Field of the Invention
The invention relates to a digital semiconductor circuit comprising a first circuit component which contains a chain of series connected flip-flop cells and a second circuit component which contains a further chain of series-connected flip-flop cells, wherein a sequence of clock pulses which serve to control the two circuit components is made from a pulse generator and wherein one of these two circuit components consists of a shift register and its shift pulse train is formed by the aforementioned sequence of clock pulses.
Prior Art
A circuit of this kind is described in the German AS 21 12 637 which corresponds to U.S. Pat. No. 3,631,402. This AS relates to a complex circuit arrangement comprising integrated circuits which are connected to one another, the individual features of which do not require to be mentioned for the present consideration. However, in these circuits, it is provided that the items of information which they supply are transmitted in parallel to an output shift register for series transfer to an input shift register which is assigned to the adjacent circuits, and from the latter are offered in parallel form to individual components of this circuit.
Thus, in the circuit of U.S. Pat. No. 3,631,402, the first circuit component consists of a shift register operated as a parallel-series converter, and the second circuit component consists of a further shift register which is connected as a series-parallel converter relative to the first circuit component. The major part of a shift register of this kind is usually formed by a chain of series-connected, identical flip-flop cells each having an input for the shift pulse train, and an information input and an information output which latter is connected to the information input of the particular following cell. Thus, the digital semiconductor circuit shown in U.S. Pat. No. 3,631,402 allows items of information to be transferred from one circuit component to another and in the case of complex circuits composed from individual modules the two shift registers can be arranged on separate chips.
A shift register is a circuit in which an item of information can be transported in unchanging form. This is due to the fact that the individual flip-flop cells (generally master-slave flip-flops) of the shift register are connected to one another in such a manner that with each clock pulse the item of information stored in the individual cell is transferred to the following cell so that the stored overall information is shifted by one step in the same direction. However, it is also possible to connect the cells of a flip-flop chain in another fashion, namely as a binary counter. Here again the operating state of the following cell is controlled by the preceding cell. However, the control is such that directly following a change in the operating state of a flip-flop cell which follows another cell even when the cell has assumed the prior operating state of the preceding cell, the preceding cell will generally change its operating state.